On the mutability of human nature

One axiom seems to have occupied the basis of philosophy, sociology, economics, and all other disciplines which concern human progress and improvement: the immutability of human nature. From the Ancient Greek historian Thucydides who reflected that “human nature is the one constant through human history,” to the early economist Thomas Malthus, who predicted that the “fixed laws of our nature” will never change, human nature defined constraints as to how we could perfect society. Most humans reasonably perceived the soul to be a supernatural, eternal, immutable entity. Regardless of religion or geography, most humans have adopted the dualist belief that an immaterial human soul exists separately from the material body. After the 17th century, when the brain was widely accepted as the true center of thought and emotion, the dualist separation of body and soul became one of biological brain and spiritual mind.

Every day, science casts into ever deeper doubt the dualist claim. Every time we discover a mechanism which robustly explains a behavior — that is, every time we identify the chemical or neural pathway which is necessary and sufficient for executing this behavior — our conception of the mind may become more physical and less spiritual. For instance, discovering the biophysical basis of opioid addiction continues to reveal how heroin — a physical molecule which exerts a well-characterized physical effect on the user — fundamentally alters the thoughts, urges, and tendencies of the addict. If one's consciousness can be fundamentally altered by purely physical means, mustn’t the origin of that consciousness be physical? For how could physical matter override a spiritual process?

Scientific discoveries continue to unravel the nervous system, sometimes untangling the knotty mechanistic explanations for our tendencies and behaviors, but usually revealing additional layers of tangled complexity. While the discovery of physical mechanisms can directly prove the dominance of biology over spirit, I argue that the discovery of additional complexity is what should truly convince us that the mind is material. One of the most cited arguments for the dualist idea is that the mind's incredible complexity could not possibly be encoded in a finite volume of matter. However, as we uncover the brain's 100 billion neurons and hundreds of trillions of synapses, how it encodes messages with activity at various frequencies, and the practically infinite permutation of this activity, this argument of the dualists quickly erodes.

In any case, we should recognize that the physical machine which controls our thoughts, movements, and consciousness is far more beautiful than the notion of an eternal soul could ever be. The brain is beautiful because it is an assembly of organic molecules which can study and understand and comprehend themselves. The brain is beautiful because it was crafted by random interactions and iterations under a relatively minute set of natural laws, within a relatively short period of time. The brain is beautiful not only because it is mutable, but because it can consciously mutate itself. We call this novel capability neuromodulation, and its existence falsifies the conclusions of Thucydides, Malthus, and all others who could not anticipate the mutability of human nature.

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